Breastpumps for use by nursing mothers are well known. They allow the nursing woman to express the breastmilk as necessary or convenient, and further provide collection of the breastmilk for later use. For some mothers, breastpumps may be a necessity, such as when the child has suckling problems, or if the mother has problems with excessive or deficient milk production, or soreness, deformation or injury of the mammilla, or like conditions which are not conducive to manual breast feeding.
Manual breastpumps are commonplace. They are relatively inexpensive and easy to transport. Examples of such manually-driven pumps are in U.S. Pat. No. 6,497,677.
Electrically-driven breastpumps are also commonplace. They may be of a substantially large size of a non-portable or semi-portable type, typically including a vacuum pump which has an electric motor that plugs into standard house current. Besides eliminating the efforts of manual pumping, some advantages of this type of pump include better controllability and regulation of the vacuum. The option of variable frequencies (rates) and amplitudes (suction levels) is often provided.
Battery-driven breastpumps have also been developed. These breastpumps have the advantages of controllability and regulation of the vacuum, as well as being easily carried. Such a battery-driven portable breastpump is described in U.S. Pat. No. 4,964,851, for example. This breastpump, sold under the name MINIELECTRIC by Medela, Inc., is lightweight and achieves good vacuum (i.e., negative pressure) regulation in preferred limits, for example, between about 100 and about 220 mmHg. The LACTINA breastpump sold by Medela, Inc. is also another type of breast pump which may be driven by battery as well as house current. It is generally disclosed in U.S. Pat. No. 5,007,899.
The prior art manual as well as motorized breastpumps have, to Applicants' knowledge, only been developed with a single type of “cycle” for a given pump. That is, the driving mechanism for generating the vacuum (negative pressure) to be applied at the breast in the more sophisticated pumps is geared to a particular sequence, or curve, of negative pressure increase (i.e., increasing suction), and then release. In these pumps, regardless of vacuum amplitude and frequency, the envelope of the curve (vacuum over time) is essentially the same, barring unintended defects occurring at extreme settings. The curve is often aimed at reproducing in some sense the suckling action of an infant, for instance.
Breast pumping can cover a range of different conditions, however, such as where the mother's nipples are sore for some reason, there is a state of significant engorgement, some nipple stimulation may be particularly desired, letdown and relaxation may be of particular interest, it may be desired to increase milk production, and so on.
As noted above, some breastpumps provide the user with the ability to vary the amount of vacuum being applied, as well as the speed of the pumping action (i.e., number of vacuum cycles per minute). In some instances, speed and vacuum level may influence each other, such that as speed increases so does the vacuum level. The basic “curve” remains fixed, however, as described above, and the user must adapt as best she can to making variations within that particular curve built into the machine, which typically has been generalized for the overall population of users.
Moreover, conventional breastpumps are not made to differentiate between different phases of the milk expression process, or equipped with a mechanism or method of operation to accommodate the different phases. That process includes, for example, a period before breastfeeding, referred to as the milk ejection period, or “letdown”, in which effective removal of the milk from the breast is initiated by the suckling action of a baby's mouth and jaw to produce or stimulate an ejection reflex, in which stored milk is released and made available for general expression. It is believed that efficient expression of breastmilk is improved by stimulating milk ejection before initiating milk expression.
“Letdown” is, of course, a well known phenomenon. The milk ejection reflex is the neurohormonal reflex resulting from the tactile stimulation of the nipple sending neuronal impulses to the hypothalamus, and the neurohypophysial release of oxytocin into the systemic circulation. The subsequent contraction of the myoepithelial cells within the breast caused by oxytocin moves milk from the alveoli into the collecting ducts and forward to the nipple. Milk ejection, or the milk ejection period, is the interval when an increased availability of milk from the nipple is caused as a result of the stimulation of the milk ejection reflex. Milk ejection in women normally lasts for approximately two minutes, but will, of course, vary from person to person. The ejection reflex will be identified in the following also as “letdown” or “ejection”.
The level of pressure applied and the intermittency of the stimulation for initiating ejection are different than the level and intermittency of the action for actually expressing the breast milk. Conventional breastpumps do not provide a method or mechanism by which a user can easily stimulate an ejection reflex and subsequently commence to efficiently express breastmilk.
A demand is therefore believed present for a breastpump that is usable to easily produce stimulation to initiate ejection, and in addition provides efficient expression of breastmilk, thereafter by operation thereof.